1. Technical Field
The present invention relates to a RFID label embedded with an inlet having an integrated circuit (IC) and an antenna. More particularly, the present invention relates to a RFID label and a method for manufacturing the RFID label to avoid creating creases at the portions of the label with different total thicknesses such as at the periphery of the embedded inlet and around the IC.
2. Background Art
An RFID label 3 as depicted in FIG. 6 has recently been prevalent in use. The RFID label 3 is attached to a part, such as a piece of merchandise, a package thereof, etc., and is used by recording thereon information concerning e.g. the name and the histories of the product and to record thereon, transmit, and manage information e.g. concerning delivery, such as a delivery destination, of the part or the piece of merchandise on which the label is disposed. The RFID label 3 is comprised of an RFID inlet 22 sandwiched between an adhesive paper sheet 2 which is comprised of a label base material 6 and a first adhesive layer 7, on the one hand and a separator 8, on the other hand. The RFID inlet 22 includes an IC 19 that has data stored therein and an antenna 18 that is connected to the IC 19 and that transmits and receives information. The antenna is disposed on one or both sides of a base material 16. The RFID inlet 22 is temporarily attached to the separator 8 through a second adhesive layer 17.
The RFID label 3 incorporates the RFID inlet 22 between the label base material 6 and the separator 8. Therefore, specialized label manufacturing equipment is used that is dedicated to the RFID label 3 and that is different from a multi-purpose label manufacturing machine.
An example of a RFID label manufacturing apparatus 20 depicted in FIG. 7 sequentially laminates the inlet 22 and an adhesive paper sheet 61 on a separation face of the separator 8 and cuts the resultant label into a die, during conveying of the separator 8. The RFID label manufacturing apparatus 20 includes in the sequence an unwinding unit 30, apparatus for performing an inlet laminating process 50, apparatus for performing an adhesive paper sheet laminating process 60, apparatus for performing a die-cutting process 70, and a winding unit 80, a waste winding unit 90 along a forward direction conveyance path for the separator 8 in.
A wound up separator roll 32 of the separator 8 in attached to a supply shaft 31 of the unwinding unit 30.
The inlet laminating process 50 attaches inlets 22 supplied from an inlet continuous body 51 to the separator 8. The inlet continuous body 51 is formed by disposing inlets 22, each including an IC 19 that has data stored therein and an antenna 18 that transmits and receives information disposed on the surface of the base material 16. The inlets are disposed on a separator 58 at specific intervals. The inlets 22 are temporarily attached to the separator 58 through the second adhesive layer 17 and are attached to a supply shaft 52 where the separator is wound in a roll as the inlet continuous body 51. The inlet laminating process 50 is performed by the supply shaft 52 for the separator, a guide roller 53, about which the separator is guided and there is a separating plate 54 that turns the separator 58 at an acute angle to the upstream direction and that causes the inlets 22 to separate from the separator 58, a pair of rolls 55 that laminate the now separated inlets 22 on the separator 8, a guide roller 56 that guides the separator 58 after the inlets 22 have been separated therefrom, and a take-up shaft 57 that takes up the separator 58, along a path of the inlet continuous body 51 in its forward direction.
The adhesive paper sheet laminating process 60 comprises acquiring an RFID adhesive paper sheet 69 by causing the adhesive paper sheet 2 to adhere to the separator 8. An adhesive raw paper sheet roll 61 is a laminated body including a label base material 6, a second adhesive layer 7 and a separator 68. It is attached to a supply shaft 62 by being wound in a roll. The adhesive paper sheet laminating process 60 is performed by the supply shaft 62, a roller 63 around which the separator 68 turns and separates, a pair of rolls 64 that laminate the adhesive paper sheet 2 on the separator 68 to form an RFID adhesive paper sheet 69, and a take-up shaft 65 that takes up the separator 68 that has peeled off and is along a path for the adhesive raw paper sheet 61 in its forward direction.
The die-cutting process 70 causes a blade to enter the separator 8 from the label-base-material side and to cut the separator 8 into a die. For example, the RFID adhesive paper sheet 69 is sandwiched between a roll with a blade referred to as a dicing roll 71 and an anvil roll 72. The dicing roll 71 is pushed onto the label base material 6 and is rotated thereby forming a cutting line. A pair of waste collecting rolls 73 and 74 disposed downstream from the dicing roll 71 separate label waste 9 from the RFID adhesive paper sheet 69.
The RFID label 3 is processed as follows. The separator 8 is unwound and fed from the unwinding unit 30, to the inlet laminating process 50. The inlets 22 are temporarily attached at specific intervals on the separated face of the separator 8 by the second adhesive layer 17.
The laminated body of the separator 8 and the inlet 22 arrives at the adhesive paper sheet laminating process 60. The adhesive paper sheet 2 is further laminated on the laminated body and, thereby, the inlet 22 becomes part of the RFID adhesive paper sheet 69 that is sandwiched by the separator 8 and the adhesive paper sheet 2.
The RFID adhesive paper sheet 69 advances to the die-cutting process 70 where it, is cut into a die having a desired label size, by the dicing roll 71 causing its blade to enter the sheet 69 from the label-base-material side.
When label waste 9 surrounding the RFID label 3 are peeled off by the waste collecting roll 73, a label continuous body 10 is completed that has the RFID labels 3 depicted in FIG. 6 arranged therein at specific intervals. The label continuous body 10 from which waste has been collected is taken up by and wound on a take-up shaft 81 of the winding unit 80 passing through a guide roll 29 to form an RFID label roll 82. The label waste 9 that is collected is taken up by and wound on a take-up shaft 91 of the waste winding unit 90. Thereafter, the RFID label roll 82 is divided into small rolls each having a predetermined length of the label roll and a predetermined quantity of labels. Each of the small rolls is finished as the RFID label continuous body 10 in the roll depicted in FIG. 8. The RFID label continuous body 10 is issued after printing on the surface thereof by a label printer 150 depicted in FIG. 3 and after writing information into the IC 19.
FIG. 3 is a schematic side view of the label printer 150. The label printer 150 is provided with a roll paper sheet feeding unit 151 and a printing unit 161 in a housing 152. The RFID label continuous body 10 that is wound in a roll is rotatably supported around a shaft 155 of the roll paper sheet feeding unit 151. Along a traveling path for the label continuous body 10 in its forward direction, there are attached in sequence a guide bar 156, a paper sheet sensor 157 that detects the presence or absence of the label continuous body 10, a pitch sensor 158 that detects intervals between the labels, and a reader/writer 159 that transmits and receives information to/from the RFID label 3 by wireless communication. A printing unit 161 downstream of the above noted elements includes a platen roller 162, a thermal head 163 that pushes on and supports the label continuous body 10 together with the platen roller 162, and a cutter unit 164 present downstream of those elements. The housing 152 is provided with an issuing window 165 adjacent to the cutter unit 164.
When the platen roller 162 is rotated, the RFID label continuous body 10 that is unwound and fed arrives at the reader/writer 159 after passing the guide bar 156, the paper sheet sensor 157, and the pitch sensor 158. Information is recorded on the RFID label by wireless communication. The RFID label continuous body 10 arrives at the printing unit 161, and images such as characters and bar codes are printed by thermal scanning of the thermal head 163. After the printing, the RFID label is discharged to the exterior from the issuing window 165 as a continuous body or is cut one by one by the cutting unit 164.
The RFID label 3 includes the inlet 22 that has protrusions and recesses and is a three-dimensional object, and the inlet is sandwiched between the adhesive paper sheet 61 and the separator 8. FIG. 9(a) depicts a cross-sectional view of the RFID label roll 82 wound in the roll. In FIG. 9(a), the contour of the RFID label roll 82 is depicted with virtual lines and only one RFID label 3 positioned at an end of the outermost circumferential portion of the RFID label roll 82 is depicted with solid lines. As depicted in FIG. 9(a), the total thickness of the RFIC label 3 differs between the portion having therein the inlet 22 and the portion having therein no inlet 22 and there only comprised of the adhesive paper sheet 6 and the separator 8.
FIG. 9(b) depicts an enlarged cross-sectional view of the RFID label 3. The thicknesses of the label base used for a printer generally is material 6 and of the adhesive layer 7 is are within a range of 70 to 100 μm and preferably about 20 μm. In contrast, the thickness of the base material 16 of the inlet 22 is 25 μm for a thin-type one and 100 μm or more for a thick-type one. The thickness of the second adhesive layer 17 that temporarily attaches the inlet 22 and the separator 8 to each other is also about 20 μm and this thickness is substantially added to the total thickness, of the inlet 22. In addition, the thickness of the antenna (which is several μm to several tens of μm) is also added to the total thickness. Although the first adhesive layer 7 applied to the label base material 6 has elasticity and flowability, the first adhesive layer 7 is unable to closely cover the inlet 22 that is thicker than the thickness of the first adhesive layer 7. Therefore, hollow spaces 46a and 46b are formed around the base material 16, which allow no contact between the adhesive layer 7 and the separator 8. The thickness of the IC, not depicted, generally is 100 μm or more and exceeds the thickness of the label base material 6. Therefore, hollow spaces are also formed around the IC.
When the RFID label 3 that is a laminated body is conveyed or is issued after printing thereon by the label printer 150, wrinkles 48a, 48b, and 48c as depicted in FIG. 10 may be formed. Around the circumferential edge of the inlet 22, wrinkles tend to be formed in portions leading the traveling direction (the wrinkle 48a), trailing the travel direction (the wrinkle 48b), and in the vicinity of the IC 19 (the wrinkle 48c). All of these portions are in the vicinities of gap lines along which gaps are generated an the total thickness of the RFID label.
When the printing is executed by the label printer 150 on the portions that have the wrinkles 48a, 48b, and 48c formed therein, normal characters and bar codes cannot be printed on the portions because the printed images are faint. No information can be read from a faint bar code and the function of a label is lost.
Formation of the wrinkles will be described with reference to FIG. 9. The RFID label 3 wound in the roll is curved in an arc as depicted in FIG. 9(a). The hollow spaces 46a and 46b are respectively formed at the head leading end and the trailing end of the inlet 22 in the forward direction of its conveyance. At these portions, the adhesive layer 7 and the separator 8 are not temporarily attached to each other. The label base material 6 in the outermost circumferential portion of the roll and the separator 8 that corresponds to an inner circumferential portion thereof each have a respective length (the circumferential length of the arc corresponding to a specific winding angle) that is different from each other.
When the RFID label 3 is unwound and fed to be flattened out as depicted in FIG. 9(C), the label base material 6 is distorted due to the circumferential length difference between the label base material 6 and the separator 8. The length of the label base material is excessive when the RFID label 3 is flattened out because the length of the label base material 6 is longer than the length of the separator 8. Therefore, a force is generated that causes the label base material 6 to contract in the longitudinal direction. The force generated concentrates on the portions at the hollow spaces 46a and 46b. Therefore, the label base material 6 in these portions is detached and lifted up from the separator 8. These portions lifted up cause the wrinkles 48a and 48B depicted in FIG. 10 to be lifted up. A portion of the label base material 6 is caused to be lifted by a hollow space formed around the IC 19 at the wrinkle 48c. 
In addition, even if no wrinkle is formed when the RFID label 3 is unwound and fed because the distortion is relatively small, wrinkles may form when the RFID label continuous body 10 is conveyed. This may occur, for example, in the case when the direction of conveying of the RFID label continuous body 10 is changed using a guide roller having a small diameter in a label manufacturing machine, etc.; where the RFID label continuous body 10 is conveyed sandwiched with a strong force by, for example, nipping rolls; or where the RFID label continuous body 10 is sandwiched by a thermal head and a platen roller and printing and issuance are executed by driving the platen to rotate as in the above label printer in the thermal printing scheme or a label printer in the thermal transfer scheme. In these cases, although no wrinkle is formed immediately after unwinding and feeding the RFID label 3 from the roll, the distorted label base material 6 is squashed by an external force and, as a result, the wrinkles 48 are formed.